Evidence of exposure to chemicals and heavy metals during pregnancy in Japanese women

Abstract

Purpose: Prenatal exposure to environmental chemicals is a growing concern, because such exposures have been shown to be associated with various diseases. The levels of chemicals and heavy metals in maternal blood, cord blood, maternal urine and amniotic fluid in Japanese pregnant women were investigated.

Methods: A total of 145 women, including 14 fetal growth restriction cases, were included in the present study. The levels of phthalates (di[2-ethylhexyl]phthalate and mono[2-ethylhexyl]phthalate), perfluorinated compounds (perfluorooctane sulfonate, perfluorohexanoic acid, perfluorooctanoic acid, and perfluorononanoic acid), pesticides (dimethylphosphate, dimethylthiophosphate, diethylphosphate, diethylthiophosphate, 3-phenoxybenzoic acid, and octachlorodipropyl ether), bisphenol A, nicotine (nicotine, nornicotine, cotinine, norcotinine, and trans-3'-hydroxycotinine), polybrominated diphenyl ethers, and heavy metals were measured. The relationship between fetal growth and the levels of chemicals and heavy metals were investigated.

Results: Phthalates, perfluorinated compounds, pesticides, polybrominated diphenyl ethers, and heavy metals were detected in high frequency, whereas nicotine and bisphenol A were almost negative. Phthalates, perfluorinated compounds, and several heavy metals were transferred to the fetus. High perfluorononanoic acid levels in the maternal blood and cord blood, and low perfluorooctanoic acid level in the cord blood were significantly and negatively associated with fetal growth.

Conclusions: The present study showed that pregnant women in Japan and their fetuses are exposed to a variety of chemicals and heavy metals.

Keywords: chemical exposure; endocrine disrupting chemicals; fetal growth; heavy metals; pregnant women.

Figure 1

Perfluorinated compounds (PFCs) levels in maternal blood and cord blood. A, Perfluorooctane sulfonate (PFOS), perfluorohexanoic acid (PFHxS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) levels. The y‐axis indicates the concentrations (ppb). Values are median (range). For statistical analysis, the Wilcoxon rank sum test were used. *P < .01. B, Correlation analysis of the levels of PFCs between the maternal blood and the cord blood using 40 paired samples of maternal blood and cord blood. P‐value and R‐value of correlation analysis are shown in each graph. Open circles indicate each case

Figure 2

Correlation analysis of the levels of heavy metals between the maternal blood and the amniotic fluid using 32 paired samples of maternal blood and amniotic fluid. Li, Mg, Ca, Sr, and Mo levels were analyzed. P‐value and R‐value of correlation analysis are shown in each graph. Open circles indicate each case

Figure 3

Levels of perfluorinated compounds (PFCs) in fetal growth restriction (FGR) and non‐FGR cases. A, The levels of PFCs (perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxS), and perfluorononanoic acid (PFNA) levels of the maternal blood (left) and the cord blood (right) are shown by boxplot. The y‐axis shows concentrations (ppb). For statistical analysis, the Wilcoxon rank sum test was used. *P < .01. B, Correlation analyses between the PFNA levels in the maternal blood or the cord blood and the birthweight. C, Correlation analyses between the PFNA levels in the maternal blood or the cord blood and the placental weight. Closed circles indicate non‐FGR cases and closed triangles indicate FGR cases